Measurement of radiation efficiency of antennas in the vicinity of human head model proposed by COST 244

In the design of antennas for portable telephones, it is important to evaluate the radiation efficiency of the antennas in the vicinity of the human body, since the radiation efficiency could decrease due to power absorption by the human body. However, if different antennas are designed by different people, and different human models are used in their evaluations, their results cannot be compared each other directly to determine which antenna has a highest radiation efficiency. Therefore, it is required to develop some canonical problems that may be utilized for comparing the numerical and experimental results of the characteristics of various antennas. Working Group 3 of COST 244 has proposed some canonical problems for comparing different numerical methods developed for calculation of absorbed power in the human head to assess the potential hazard caused by the use of mobile communication devices. The objective of this report is to measure the radiation efficiency of antennas in the vicinity of the human head models defined by COST 244 to investigate how the radiation efficiency changes with the different models. The pattern integration method is used as the measurement method. The experimental results are shown and compared with the numerical results by using the finite difference time domain (FDTD) method.